Sewing machine



Aug. 23, 1938.

- N. v, cHRlsTl-:NSEN ET A1.

' SEWING MACHINE Filed Jan. 25,1936

$5 Sheets-Sheet lv Charlas-171mm@ l Aug. 23,' 1938.

N. v. cHRlsTENsl-:N ET A1. 2,128,120

SEWING MACHINE Filed Jn. 25, 19:56 :5 sheets-sheet 2 WTORNE YS.

Aug. 23, 1938. N. v. cHRlsTENsEN ET AL 2,128,120

SEWING MACHINE l3 Sheets-Sheet 5 Filed Jan. 25, 1956 v il TOR/VA E YS Patented Aug. 23, 1938 'SEWING MACHINE Norman V. Christensen. and Charles F. Rubel,

Chicago, Ill..

minors to Union Special y Machine Company, Chicago, Ill., a corporation of Illinois Application .Imam z5, 193s, serial No. V60,764 'z claims.y (ci. 11e- 197) This invention relates to sewing machines; and it `has reference more particularly to a. chain stitch sewing machine of the type wherein the rotary main or driving shafts from which the '5' needle, looper and ieed mechanisms all derive their movements are journaled in horizontal arms overhanglng ilat oblong bed plates or work supports. Such machines are extensivelyused in the manufacture of bags of burlap, canvas and the like as well as in other connections.

The aim of our invention is to enable operation of sewing machines of the type specifically re- Ierred to at higher speeds than possible heretofore, with a view toward obtaining increased u production from them.

. This objective we realize in Practice, as hereinafter more fully described, by utilizing light rotary parts to the utmost extent, and translating the rotary motion of such parts into recipro- Y catory motion at points or regions local to those elements (e. g. the needle, looper or loopers, feed elements, etc.) which require reciprocation through provision of correspondingly iight, structurally-rened intermediate connections which are dynamically balanced and smooth in'- their action so that noise, vibration and wear are re,

:wlw-1 @ther objects and attendant advantages will appear :from the following detailed description of the attached drawings, wherein Fig. I is a Fig. m show's'the needle arm oi? the machine in plan; and

Fig. il! is a plan sectional viewol the machine taken as indicated by the arrows IV--IV in Fia. l.

40 As herein illustrated, the irame ol our improved sewing machine comprises a nat horisontal oblongbed plate or work support i, with an integrally formed hollow standard 2 opstanding from one end thereof and sustaini a hollow overhanging arm i above said work support, said arm terminating at its free end in a head il. The machine is primarily designed lor mountingupon the top oi au operetors table T (Fig. l) with the bed plate or worl: support l suhstantially hush,

g, and the parts ndant therefrom projecting down through an opening Q in the table. in instances where it is desirable to have the bed plate i elevated, or when the machine is to be sustained on a narrow plank or beam as in bag factories,

g, a mounting or base such as shown and described in a copending patent application Serial No. 58,672 filed on Jan. 1 1, 1936, by Norman V. Christensen, one vof the present applicants, may be used. Journaled in bearing bushings 5 and 6 set into the hollow of the overhanglng arm 3 is 5 the main or drive shaft 1 of the machine, the

rear end of said shaft extending through the bearing 6 to the exterior where it is provided with a combined hand and belt wheel 8 so that the machine may be operated either manually or 10 by power. As shown, the bearings 5 and 6` have oil ports 9 and I0 which'respectively register with vertical oil ducts il and i2 accessible at the top of the overhanging arm 3. Guided ior vertical reciprocation inupper and lower bushings y|3and 15 it set into the head t, is a vertical bar i5 which carries the needle it., Up and down movements are imparted to the needle bar ib by means which includes a dynamically-balanced cranlr member i'i whereof the cranlr pin it is coupled, by means 20 of a link it, with a pin it projecting rearward from a split collar il which is secured to said needle bar near the top within the hollow of the head t, by a clamp screw il. The projecting end of the pin 2t is attened as at il to engage a 25 vertical guideway it within the hollow head t,

and is thereby steadied in its movements. Free to rotateon the pin id is a ball it which engages the spherical cavity oi a split bearing boss il at the lower end oi the linlr iii. The cap piece 3o it oi the bearing boss il is formed with a scoop 2d which dips up lubricating oil from a small well tu in the bottom oi the head t and conducts it to the surface of the bali it, aportion oi such oil nding its way to the pin it by way oi one or Y: more radial ducts ti in said ball. 'lfhe described construction oi the link it constitutes one of the features of the present invention and is advany tageous in that said link and its connections are "rendered sell-aligning, Seli-onlne and smooth acting, with preclusion oi binding and heating oi the end bearings of said linis when the machine is operated at high speeds. if there should be any tendency oi either one oi the bearing surfaces oi the ball it to sticls, the other oi said surfaces uwill obviously continue to function as a pivot.

. The vertical presser bar di of the machine is guided near the bottom in a dant bearing projection dit oi the head d, and is held against rotation through engagement oi the lateral pror lection Bil of a collar it thereon, in a vertical guide tt at one side of said head. The upper end oi the presser bar t2 is conned to slide in a screw bushing 37 threaded into the upper part oi the bead il,said bushing bei longitudinaliy/ slotted as'at 33. The presser bar 32 is acted upon by a double leaf spring 39, of which the forward end extends through" an opening i0 in the back of the head Ll (Fig. III) and into the slot 38 of the bushing 3l to engage the rounded top of said bar, seev Fig. II. The rear end of the spring 33 is apertured as shown in Fig. III to engage an anchorage stud projection il on the overhanging arm 3. The pressure of the spring 39 is regulatable by a set screw l2 threaded in a bracket lug d3 at the top of the arm 3; and a jam nut iid functions as a means for holding the set screw in adjusted positions. Due to the influence of the leaf spring 39 upon the bar 32, the presser foot l5 at the lower end of the latter is maintained in yielding engagement with the fabric being sewed in the machine.

In order that the presser foot |55 may be raised clear of the work support i when desired or required, a lifting latch lever 08 is provided, said lever being fulcrumed to swing about a screw dl engaged in the front of the head l, and having a cam surface 38 to coact with a stud projection H9 on the collar 35 aixed to the presser bar 32, see Fig. II.

Extending longitudinally of the machine beneath the work support l in parallel relation with the main shaft 'i is a transmission shaft 50, which, at its rear end, is journaled in a bushing 5| set into the front wall 52 of a lubricant sump 53 integrally formed with, and depending from said work support. As shown in Fig. I, the lubricant sump 53 is in direct communication with the hollow of the standard 2, and closed at the bottom by a removable plate 55. The shaft 50, it will be noted, extends into the lubricant sump 53 and to its end is secured a helical gear pinion 56, the hub 51 of which abuts one end vof the bearing bushing 5| while a collar 58 abuts against the other end of said bushing to hold said shaft from shifting endwise. The gear pinion 56 is driven, through an intermeshing idler gear wheel 59, from a helical gear pinion 60 secured on the main shaft 1 directly adjacent the bearing 6 of the latter.y The idler gear 59' is free to rotate on a fixed transverse shaft 6| within the hollow of the standard 2, and the thrust thereof in opposite directions is opposed by collars 62 and 63 on said shaft 6| abutting opposite faces of the hub 64 of said gear wheel. The gear train 56, 59 and 60 is lubricated through splash oil carried up from a supply within the sump 53. In practice, the idler gear 59 is made from suitable sound and wear absorbing material, and is preferably so proportioned with respect to the pinions 56 and 60 that theA points of contact thereof with the latter gears constantly change with resultant uniform distribution of the Wear. The communication of motion from the upper or main shaft 'l to the lower or transmission shaft 50 is thus effected smoothly, positively and noiselessly. The gear drive herein` shown and described is the same in principle and operation as that disclosed in applicants copending application Serial No. 670,186 filed on May 9, 1933.

At its left hand end (Figs. I and IV), the transmission shaft 50 is integrally formed with a pair of spaced crank heads 65, 66 with a connecting ball crank pin 61, from which the looper mechanism of the machine receives its movements as will be presently explained. The terminal head 65 has a socket to receive the contiguous end of a supplemental shaft 68 which is made fast by screws 69. As shown in Fig. IV. the supplemental shaft 68 is journaled in spaced pendant bearing lugs l0, "il of the work support i, and, in `eect, is a coaxial continuation of the transmission shaft 50. .incident to assembling the machine7 the collar 58 and the bushing 5| are mounted on theshaft 50 and the right hand end of the latter is inserted through the bearing boss l2 on the oil sump 53, whereupon said bushing is pushed into place and secured by the set screw shown at W3, see Fig. I. The construction of the lower shaft of the machine from the two parts 50 and 53 as shown and described is advantageous in that it facilitates assembling of the machine, and also in that it aords a separable crank 'l at the juncture between said sections.

Cooperating with the needle i5 beneath the Work support i of the machine, is a looper 'M which is carried by a vertical arm 'l5 fulcrumed on a stud i6 projecting from the looper rocker lll which is secured by set screws i8 to a rock shaft i9 having its ends journaled in bushings and 8i respectively set into the bearing lugs l@ and "il, rIhe shaft 39 is rocked through the medium of an arm 82 clamped thereto and connected to the strap 83 of an eccentric 34 on the supplemental shaft 68, see Figs. I and IV, with resultant impartation to the looper of its needle -avoiding movements. The holder or carrier 'l5 for the looper il is oscillated about the fulcrum 'i6 -in the performance of its loop taking functions through a horizontal link 85 which has split bearings 86 and 81 at its opposite ends respectively engaging a ball stud 88 on said 4carrier 'l5 and a similar ball stud 89 on an arm 90 extending upward from an oscillating sleeve 9|. As shown, this sleeve 9| is aiiixed to a transverse rock shaft 92 whereof the ends are journaled in bearing bushings 93. 94 set into spaced lateral projections 95, 96 of the bearing lug 'il hereinbefore referred to. The oscillating sleeve 9| also has a horizontal arm 91 which terminates in a ball end 98 and which is coupled with the crank pin 61 on the transmission shaft 50, by a link 99 also formed with split bearing ends |00, |0|,.

to respectively engage said ball and the crank pin. By employing balanced parts with ball joints in the looper mechanism just described, and through provision of the crank pin 61 in lieu of an eccentric such as is ordinarily used in machines of this type, friction and wear is reduced to a minimum so that the movement of the mechanism is rendered smooth and easy and noiseless.

The means provided for progressively advancing the fabric in the machineincludes a feed dog |02 which, as shown in Fig. II, is secured, with capacity for vertical adjustment, to a feed bar |03 `by means of a screw |04. Fixed in a boss |05 at the rear end of the feed bar |03, is a trans-l verse pin |06 whereof the ends engage spaced bearing bosses |01, |08 of a yoked rocker |09, which, in turn, is secured to a rock shaft ||0 whereof-the ends are journaledrespectivelyif the bearing of the lug 10 and another bearing lug ||2 pendant from the work support said rock shaft being held against shifting axially by collars ||3, Ill thereon'which respectively abut the lugs I and ||2 at their inner sides, see Fig. IV. Secured to the outer end of the rock shaft ||0, preferably by welding, isa horizontal arm ||5 which reaches forwardly and which atv .its outer end' has pivotal connection at ||6 with the lower end of a vertical link ||1 whereof the upper end` is split to clamp a bushing ||8 engag- Y ing a crank pin ||9 on a crank disk'l20 amxed 75 .forwardly curved arm projection Wt of the feed bar |03, see Fig. II. The feed mechanism just described isv generally similar to that featured in U. S. Patent No. 1,817,727 to Wohlpart, and, is hereinafter claimed only in combination with the' other and cooperating mechanisms of the machine. It is to be particularly noted however that in the present instance, the feed rocker shaft lit passes through a hearing in the lug iii disposed between the feed rocker itt and the arm H5. This arrangement is advantageous in that it precludes exertion of side thrust or torsion against the feed rocker idd and thus eases ,the action of 'the feed mechanism.

In order that tight stitches may he formed hy the machine, there is provided a nipper or intermittent tension means for the needle ihre, this means being shown in Fig. I as comprising a vertical sleeve W5 which is fast in a boss t28 at the top of the overhanging arm 3, and which is surmounted by a regulatable tension device it'i adapted to be actuated by an eccentric t28 on the main shaft 'I through a thrust pin or plunger itt guided in said sleeve.

Also, during the sewing, the slack of theviooper thread is absorbed by a take-up device which is generally designated by the numeral |30 in Figs. I and IV. This take-up comprises a rotary cam disk |3| which is secured to the supplemental shaft 03 and which projects through a slot |32 in an inclined guard plate |33 suitably secured beneath the work support of the machine and overreaching said shaft. Fastened to the guard plate |33 by screws |33 is 'a upshaped holddown tongue |30 of wire (between which and the plate, the llooper thread passes), and thread guides |31 at opposite sides of the slot in said plate. The

rotary take-up just described corresponds inconstruction and principle of operation with that forming the subject matter of a copending application Serial No. 24,495, filed on June l, 1935 by Charles S. Thompson.`

. From the foregoing it will be seen that in 'our improved sewing machine, we have utilized but two rotating shafts which are interconnected hy a gear train drive system, and from which the rotary movements are translated, through light vand dynamically balanced anti-friction parts,

into reciprocatory movements oi' the needle, the looper and the feed dog, at regions local to these cooperating elements. In this way, we have edctively avoided strains and restraints in the moving parts such as would result in excessive heating to theadvantage that the machine can be operated at much higher speeds than heretofore attainable.

Having thus described our invention, we claim: l. In a sewing machine.' a frame with a work supporting plate and a hollow overhanging a 'sustained by a hollow standard at one end of said plate; a rotary shaft journaled within the hollow of said arm; a needle bar confined to verticali reciprccation in a head at the free end of the overhanging arm; a counterbalanced crank at the forward end of the shaft: a crank pin on said crank; and a connection between the needle har and the pin of the crank including a link, a lateral pivot on said bar in engagement with a boss at one end of the link, ahall free to rotate on the crank pin as an axis and engaging a spherical bearing surface in a hoss at the opposite end of the link.

2. In a sewing machine, a frame with a work supporting plate and a hollow overhanging arm sustained by a hollowvstandard at one end of said plate; a rotary shaft journaled within the hollow of said arm; a needle har conned to vertical reciprocation in a head at the free end of the overhanging arm; a balanced crank at the forward end of the shaft; a crank pin on.,said crank; and a connection hetween the needle bar and the pin of the crank including a iaterai stud on said roar in engagement with a bearing hoss at one end of the link, a hall free to rotate on the crank pin and engaging a spherical hearing surface in a `boss at the opposite end of the link, the last mentioned hoss having a scoop projection adapted, during rotation of the crank, to scoop up oil from a well within the head for lubricating the hall and the crank pin.

3. In a chain stitch sewing machine, a frame with a work supporting plate and a hollow overhanging arm sustained by a hollow standard at one end of said plate; a pair of longitudinal shafts, one journaled within the hollow arm, and the other journaled beneath the work supporti plate; a train of intermeshing gear wheels forming the drive connection between the two shafts, said gear wheels being enclosed in the hollow of the frame standard and a counicating oil sump pendant lfrom the work support; a needle bar conned to vertical reciprocation in a head at the free end of the overhanging arm; a cooperative looper, and a feed element below said Work support; means adjacent the forward ends of the two shafts whereby their rotary movements are converted respectively into reciprocatory movements of the needle bar, and into oscillatory and reciprocatory movements of the looper and the feed dog; a tensioning device for the needle thread; and a rotary cam on the upper of the two shafts for actuating thetensioning device to intermittently apply tension on a needle har confined to vertical reciprocation in a head at the free end of the overhanging arm; a cooperative'iooper, and a' feed element loelow said work support; means adjacent the forward ends of the two shafts whereby their rotary movements are converted respectively into reciprocatorr movements of the needle bar, and into oscillatory and reciprocatory movements of the looper andthe feed dog; and tension devices respectively for the needle and looper threads controlled hy rotary means respectively on the upper and lower Mits.

5. In a chain stitch sewing machine, a fre with a work supporting plate and a hollow overhanging arm sustained hy a hollow standard at one end oi said plate; a pair oi icngitudinai shafts, one journaieci within the hollow arm, and the other journaled beneath the work supporting plate; a train o intermeshing gear wheels forming the drive eonnectionhetween the two shafts, said gear wheels beine enclosed in the "noilow of the frame standard and a. communicating oil sump pendant from the Wort: support; a needie bai' confined to verticai z'ecipi'ocation in a head the free end. of the overhanging e, cooperative looper, and a feed element ioelow saisi work support; means adjacent the forward ends of the two shafts wi'ieseoy their" rotaiy inove ments are ccnveiteci sespectiveiy into i'ecipiom eatery movements of the needle bei, and into oscillatory and ieciprooatoiy movements oi the iooper and the feed doe; a tensioning device ici` the needle thread; a rotary cam on the upper the two shafts for actuating the tensioning de vice to inte'fmittentiy appiy tension on the needle thread; and a rotary tension device for the loopei.e thread actuated from the ioweil sloai'tq e. in a sewing machine Work-supporte@ aieaieo nfieciianisnri ccopeieting with the needle "neiow the Wori-supporting plate; anni a longitudinsi sine-ft composed of two axially-aligned sectione with a orfani; termed at one enc?, oi' one of saisi sections for actuating the complementai :stitchu forming mechanism, and having a socket within which the contiguous ene. of the other section is received and secuiee..

NORTMN V. CHRSTENSEN. CHARMS F. RUBEL. 

